Preferred conformations of the backbone and side‐chain of the amino acids, norvaline, leucine, phenylalanine, tyrosine, tryptophan, and histidine obtained by calculating the energies of conformations are reported. The conformations of non‐aromatic side groups are restricted to only certain values of χ1and χ2, and the backbone conformation is the same as shown for aminobutyric acid having a single γ ‐methyl group. The aromatic side groups prefer a perpendicular orientation about the bond Cβ‐Cγ and deviations from this orientation are characteristic of the position of the γ ‐atom. The experimentally observed conformations of amino acids with S‐atoms and aromatic groups in the side‐chain are compared with the theoretical predictions and the agreement is fo